Radio-Frequency Ablation of Tissues using the ADINA-F Joule Heat Capability

The Joule Heat modeling in ADINA-F is used to solve problems
where heating of materials occur due to the existence of an
electric current.
A common application of this feature is the radio-frequency (RF) ablation of tissues. This is an important medical
technique used for the therapy of cardiac arrhythmias and lesions
in subcortical structures of the brain. The ablation is carried out
delivering a RF current (300 kHz to 1 MHz) through an electrode
embedded in the treated tissue. The high current density that
appears neighboring the electrode tip induces a volumetric
heating due to the Joule effect. Therefore, the temperature of the
tissue surrounding the electrode increases uniformly from 37 to
above 50 degrees Celsius. Moreover, the temperature of the
tissue must never exceed 100 °C to avoid charring and tissue
micro-explosions.

The animation depicts a detail of a catheter and electrode assembly.
The electrode tip is embedded in the tissue for a 60-second
ablation cycle. On top of the tissue there is a blood stream
flowing perpendicularly to the electrode and catheter axes. The
transient simulation predicts the evolution of the temperature
distribution in the tissue as well as the blood. The results can be used to optimize
the design of the electrode shape in order to avoid undesirable
hot spots. The simulations are also a cost-effective way of
improving the quality of the therapy by studying the effect of
different parameters such as blood flow rates, ablation cycle
duration and electrode positioning.